An electric vehicle (referred to as “EV”) needs to be equipped with a large capacity battery to ensure a sufficient running distance for practical use. However, the size of the battery itself is increased and thus there is not sufficient space inside a cabin for the battery. Accordingly, the battery is sometimes mounted outside of the cabin, for example, under a floor of the vehicle.
As shown in FIG. 5, battery modules 4, each of which is formed by combining battery cells 24, are surrounded by a battery pack enclosure 5 made of metal or resin to form a battery pack 3. When the battery pack enclosure 5 is mounted outside of the cabin, the battery pack enclosure 5 is waterproofed to prevent electric leakage.
Also, as shown in FIG. 5, an electricity control circuit 25 such as an electricity connection circuit and a control unit is provided inside the battery pack 3. Furthermore, a power shut-off mechanism 6 serving as a service plug for ensuring working efficiency during maintenance is provided by an on-off switch (not shown) at such a position as to divide the voltage of the battery modules 4 connected in series.